As known, a liquid-crystal has optical aeolotropy and is used for an indicator. The liquid-crystal indicator can be driven with a low power consumption and can be designed compactly so that it can be utilized as an indicator in a vehicle. For example it can be used for a speedometer, clock or to display an abnormal indication. In a vehicle, plural indications are often indicated alternately at predetermined time intervals because of the limitation of display space.
The molecular structure of the liquid-crystal is not stronger than the crystal structure so that the molecular arrangement is rearranged or its coeffecient of viscosity is changed easily by an electric field, a magnetic field or temperature. Specifically, as shown in FIG. 8 the drawings, the response time of a liquid-crystal increases rapidly in accordance with temperature drops, because the viscosity of the liquid-crystal increases at low temperature. In FIG. 8, "RISE" shows a response time when voltage is applied to the liquid-crystal, and "DECAY" shows a response time when applied voltage to the liquid-crystal is stopped. If a vehicle, having a liquid-crystal indicator, is in a low temperature condition and plural indications are to be indicated alternately by the indicator at predetermined time intervals, two indications may overlap each other because of low response.
This problem is recognized in the Japanese Utility Model No. 101789182 issued on July 7, 1982 and a solution is offered. This solution applies a constant temperature control to a liquid-crystal indicator, however, this makes the volume of the indicator including the control quite large so that layout of the indicator in the vehicle is difficult and restricted.